There are currently an estimated 40,000 incidences of cardiac arrest every year in Canada, most of which take place outside of hospital settings. The odds of an out-of-hospital cardiac arrest currently stand at approximately 5%. In the U.S., there are about 164,600 such instances each year, or about 0.55 per 1000 population. There is a desire to decrease these out-of-hospital incidences of cardiac arrest. Certain places, such as sports arenas, and certain classes of individuals, such as the elderly, are at particular risk and in these places and for these people, a convenient solution may be the difference between survival and death.
Cardiopulmonary resuscitation (CPR) is a proven effective technique for medical and non-medical professionals to improve the chance of survival for patients experiencing cardiac failure. CPR forces blood through the circulatory system until professional medical help arrives, thereby maintaining oxygen distribution throughout the patient's body. However, the quality of CPR is often poor. Memory retention of proper CPR technique and protocol may be inadequate in most individuals and the anxiety of an emergency situation may confuse and hinder an individual in delivering proper treatment.
According to the journal of the American Medical Association (2005), cardiopulmonary resuscitation (CPR) is often performed inconsistently and inefficiently, resulting in preventable deaths. Mere months after the completion of standard CPR training and testing, an individual's competency at performing effective chest compressions often deteriorates significantly. This finding was found to hold true for untrained performers as well as trained professionals such as paramedics, nurses, and even physicians.
The International Liaison Committee on Resuscitation in 2005 described an effective method of administering CPR and the parameters associated with an effective technique. Parameters include chest compression rate and chest compression depth. Chest compression rate is defined as the number of compression delivered per minute. Chest compression depth is defined as displacement of the patient's sternum from its resting position. An effective compression rate may be 100 chest compressions per minute at a compression depth of about 4-5 cm. According to a 2005 study at Ulleval University Hospital in Norway, on average, compression rates were less than 90 compressions per minute and compression depth was too shallow for 37% of compressions.
Other studies have found similar deficiencies in the delivery of CPR. One 2005 study at the University of Chicago found that 36.9% of the time, fewer than 80 compressions per minute where given, and 21.7% of the time, fewer than 70 compressions per minute were given. The chest compression rate was found to directly correlate to the spontaneous return of circulation after cardiac arrest, so it is very important that the optimum rate be achieved for maximum chances of patient survival.
In addition to too shallow compressions, too forceful compressions may also be problematic. Some injuries related to CPR are injury to the patient in the form of cracked ribs or cartilage separation. Such consequences may be due to excessive force or compression depth. Once again, lack of practice may be responsible for these injuries.
Positioning of the hands is another parameter that may be considered when delivering CPR. It has been found that an effective position for the hands during compression is approximately two inches above the base of the sternum. Hand positioning for effective CPR may be different depending on the patient. For example, for performing CPR on an infant, an effective position may be to use two fingers over the sternum.
It has been shown through numerous studies that one of the primary reasons behind poor CPR quality is a lack of effective CPR training. Many individuals are apprehensive to take lessons in an unfamiliar environment. Others forget their skills soon after the completion of training. Therefore, a device that allows an individual to be trained and re-trained in CPR in the comfort of their home at minimal cost is desired.
Embodiments of the present invention include a device that enables the use of removable and portable electronic devices, such as consumer electronic devices with appropriate internal sensory to be used in the objective training of proper CPR technique. Such devices include an enclosure that houses the electronic device, which may be, for example, a cellular phone, personal digital assistant, game console controller or other digital device. In a preferred embodiment, the electronic device may contain an accelerometer or other type of sensor capable of measuring motion, movement or position.
The enclosure housing the electronic device may be, in some embodiments, a manikin resembling a human or human torso. In a preferred embodiment, the enclosure may possess the characteristics of a human chest. The enclosure may contain a spring or other similar component enabling the enclosure to be resistively compressed during the CPR training process. The amount of force required to compress the enclosure a specific distance may be similar or identical to that require to compress a real human chest. The enclosure may completely enclose the electronic device or may leave a portion of the device exposed. In a preferred embodiment, the enclosure is a spring loaded manikin having the electronic device inserted into a cavity in the chest area.
Embodiments of the present invention may also incorporate a feedback device capable of relaying CPR data to a student using the device. The feedback device may be a separate component with a facility to relay relevant data both visually and audibly. The feedback device may communicate with the electronic device within the enclosure through a number of ways. The feedback device may be tethered to the enclosure or the electronic device within the enclosure. Alternatively, it may communicate with the electronic device through wireless communication such as Bluetooth or wifi. If the enclosed electronic device is a game console controller, the feedback may be displayed on a television screen and the data may be transmitted to the console wirelessly or through the controller's tether. The feedback may be relayed to the user or student in the form of an interactive game incorporating challenges and simulations.
Embodiments of the present invention may be capable of determining chest compression depth and rate. The depth may be measured using a sensor within the electronic device, such as the accelerometer inside the Apple iPhone or the Nintendo Wii game console controller. The depth and rate of chest compressions may be calculated using other sensor modalities within these devices.
Other CPR relevant parameters may also be determined, such as chest recoil and proper hand position of the student. For example, tactile buttons or touch screens may be used to determine proper chest recoil by detecting the full release of the student's hands following a chest compression. Proper compressions require full chest release and the activation and deactivation of certain buttons may be used to signal this release. Buttons may also be used to determine proper hand position. The device may be configured so that proper hand placement during CPR activates certain buttons on the electronic device. These buttons, when activated, denote the hands being properly placed. The touch sensitive display on certain electronic devices may be used instead of the buttons to determine chest recoil and hand position. The force applied to the display may be used to determine proper chest release following a compression. Proper distribution of force across the display may also be detected and used to determine proper hand placement. This is particularly suited to multi-touch display devices such as the Apple iPhone or iPod touch music player.
Embodiments of the present invention may also incorporate a facility for detecting proper ventilations. A ventilation bag, which may be replaceable, may be placed within the enclosure and beneath the electronic device. A proper ventilation delivered by the student may inflate the bag causing the electronic device to rise a certain height dependent on the volume of air. The amount of movement of the electronic device may then be determined using its internal sensors, such as an accelerometer. The volume of each ventilation delivered by the student to the enclosure may be measured accurately and shown to the student.